I purchased the 2 Tees 4 x4 x2 from a big box store and when I wanted to install them I noticed some crack looking on them . After talking to the plumbing associate about it , he assures me that there is nothing wrong with them . I went today to take a look at another big box store at the same item and it looks perfect .

Am I or will I be in trouble if installing them ? Here are some pics .

I can assure you that those are not or looking like any mold marks I've ever seen . It looks more like shrinking stress cracks and they are carried from one side to the other of the thickness -- meaning you can clearly see it on the inside as well as on the outside and follow the exact same path on the Tee .

They are mold marks. From the picture there are at least three injection points where they inject the ABS material into the mold. The lines you see are where the material meets up inside the mold from each injection point as it is filled. Nothing to worry about.

Easy to test: put some significant "stress" on those pieces. If the so-called "crack" doesn't open up then it most likely isn't.
I've seen genuine cracks on ABS fittings from the BigBox, but I'm sure it was from some jerk returning his oops to the store
and some clueless clerk tossing them back in the bin.

Using the same manufacturing technique it is possible for the stress to be located on the same area . It may be interpreted as a '' cold joint '' during fabrication but , since I didn't see anything like these before I don't know if it is safe -- in the long run -- to be installed . It may be '' nothing to worry about '' , but would someone install them and warranty the job ?

For now, I will keep them as a reminder '' to check them before buying them '' . FWIW , all of the Tees 4x4x2 from the respective BBS had the same '' ........ '' on them .

Going back 20ish years I worked for a manufacturer of telephones, and other consumer products. I had quite a bit of involvement with plastic injection molding in Hong Kong and Mexico. I do believe we are looking at mold marks, but my memory banks are failing me. It may be "normal" for this grade of product. It could be due to faulty temperature control of the mold. Here is a forum where you may be able to get a very knowledgeable opinion on those photos:http://www.linkedin.com/groups/plastic411-com-forum-plastic-experts-2644080/about

If you find out anything, we would very much appreciate some feedback.